The garden beetle itself is quite harmless. Its larvae are different: the grubs can cause enormous damage to the lawn.
A well-groomed lawn is the hallmark of many front gardens, parks or sports facilities. The larvae of the garden beetle can quickly throw a spanner in the works. The garden chafer itself is similar to the cockchafer and belongs to the common family of scarab beetles. The larvae live on the lawn roots and ensure that gaps in the lawn and yellow spots cause displeasure in midsummer. We will now tell you how to use biological means to combat the garden beetle and what hobby gardeners can do to protect the green space from the voracious beetle larvae.
Recognizing garden beetles
So that the garden beetle can be distinguished from the related cockchafer, Japanese beetle or June beetle, you should pay attention to a few special characteristics:
Differences in size:
- Garden beetle=8 to 11 millimeters
- May beetle=20 to 30 millimeters
- June beetle=15 to 18 millimeters
- Japan beetle=8 to 12 millimeters
Body type differences:
Garden Beetle
- Body densely hairy
- light brown wing cover
- metal green pronotum
- short antennae ending in three lamellae
May beetle
- Elytra, head and pronotum dark yellow to light brown
- Hairless Body
- Feelers end in six lamellae
June beetle
- Elytra, head and pronotum dark yellow to light brown
- three ribs on the side
- dense hairs on the pronotum and the bases of the elytra
Japanese Beetle
- green pronotum
- tufts of white hair on abdomen
Larvae of the garden beetle
The larvae of the garden beetle are called grubs and can be recognized by the following features:
- whitish colored
- about 1.5 centimeters tall
- Head Cap Dark Colored
- Thorns on rear part
- posture strongly bent in the ground
Injurious image of the garden beetle
There must be clear differences between thedamage caused by the adult beetle and the damage caused by the larvae.
| Developmental stage of the garden beetle | Damage |
|---|---|
| adult beetle | • Smaller bites and holes in roses, cherries, apples, oaks or birches • Occurrence between May and July • Damage of minor importance |
| larva | • Turf may initially appear to have been dug out • Brown patches in lawn • Wasted grass • Mottled patterns in lawn • Left untreated Lawn dieback |
Tip: If the lawn appears to be badly affected, blackbirds or other birds may have helped out, as these are what the grubs prefer to eat.
Fighting garden beetles
As already mentioned, the adult beetles do little damage during their short summer lifespan. Fighting is therefore not necessary.
Gugs can cause more permanent damage to the lawn, but they rarely appear in large numbers in allotments. The larvae pose a far greater problem on golf courses or football pitches, where the quality of the lawn suffers significantly and sporting activities appear to be endangered, especially when the aforementioned secondary damage from scratching birds is added.
Tip: Fighting the larvae of the garden beetle makes sense from a concentration of 100 larvae on an area of one square meter.
You can check for yourself how many grubs are in the lawn. The lawn does not have to be excavated over a large area. If there are 25 beetle larvae in a quarter of a square meter, the following methods of control are definitely advisable.
Fighting garden beetles with nematodes
Use nematodes against the grubs - © LariBat / stock.adobe.com[/caption] This method is particularly gentle and does not pose a threat to other plants or domestic animals. Nematodes are small roundworms that act specifically against grubs or vine weevil larvae.
The nematode species Heterorhabditis bacteriophora has proven effective in combating the garden beetle. The threadworms penetrate the body of the larvae and deposit a bacterium there that is deadly for the grubs. The grubs die after two to three days and are eaten by the nematodes. The roundworms then leave the lawn and look for a new host.
When should the fight take place?
The flight of the garden beetle ends at the end of September at the latest. The application of the nematodes can start about six weeks later. The floor temperature should not fall below twelve degrees. Make sure the lawn stays moist, because the nematodes die when it's dry.
Hint: Nematodes have a short lay ability. After purchase, they should be deployed quickly. Stored in the fridge, the nematodes will keep for about a month.
How to fight it?
Spreading the nematodes is easy. However, some things should be considered. The roundworms react sensitively to sunlight. Therefore, application should be shifted to the evening hours and take place on a cloudy day.
The nematodes are in a powdery state. Follow the instructions and stir the powder into some water. This will make a stock suspension and you can use multiple batches of it to fill the watering cans and create a certain supply of nematodes.
Tip: Use up the nematodes completely, overdosing is not possible.
So that all nematodes are flushed into the lawn, the lawn must be treated again with water, since many nematodes stick to the blades of grass. The additional watering should be carried out no later than half an hour after the treatment, since the roundworms die off in the event of drought.
Here is another video instruction for spreading the nematodes:
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Use Garden Beetle Traps
The beetles are not killed with special ground beetle traps, only controlled. This measure allows conclusions to be drawn about a possible garden chafer beetle plague. The traps can be set up or hung on trees. It contains an attractant that attracts the beetles. The beetles fall into a funnel. If the vessel fills up within a short time, it can be assumed that there are numerous grubs. To be on the safe side, the soil sample already described can be taken and the beetle larvae counted.
Hint: The garden beetles will be released again. Only the grubs have to be fought if necessary.
How can the garden beetle be prevented?
Beetle flight begins in May. So that the domesticIf the lawn is not used for laying eggs, you should choose a higher cutting height when mowing the lawn from this point on. This can reduce the occurrence of malware by more than half.
The garden beetle prefers to lay its eggs in a dry and slightly sandy lawn. If the lawn is properly watered, there is a likelihood that the lawn will be avoided.
Garden beetles can be indirectly prevented even when laying out a garden. If the planting of various host plants is avoided, the occurrence of the beetles can also be reduced. This measure is particularly relevant in areas that already have a high incidence of beetles.
The following plants are preferred by the garden beetle:
- Roses
- Willows
- Hazelnut
- Birches
- Apple Trees
- oaks
- Poplars
- Mountain
- Pear Trees